Improvement in gr



UNITED STATES PATENT, OFFICE.

CORNELIUS BOLLINGER, OF HARRISBURG, PENNSYLVANIA.

IMPROVEMENT IN GRINDING-MILLS.

Specification forming part of Letters Patent No. 39,793. dated September 8, 1863..

T 0 all whom it may concern Beit known that I, CORNELIUS BOLLINGER, of Harrisburg, in the county of Dauphin and 7 State of Pennsylvania, have invented certain Similar letters of reference indicate corre-.

sponding parts in the several figures.

It is wellknown to everyone who has had any.

experience 'in milling that a run of stones requires the almost constant attention of the miller to prevent them from grinding either too fine or too coarse. The reason of this variation in the grinding lies in the fact that the spindle being heavily laden, and at times moving with considerable velocity, becomes heated by the friction of the followers, (which are necessarily set snugly against the spindle to keep it from trembling,) and expands and throws the runner a greater distance from the bed-stone, and consequently they do not grind as fine as before. Then, again, if the supply of grain should be stopped for a while, the la bor of the spindle being reduced, the tendency of it is to cool and contract, and consequently to bring the stones nearer together, so that when the grain is again supplied to them they will grind too fine. To compensate for this variation no provision is made except that of adjusting the runner higher or lower, according as the stones are grinding too line are too coarse. This adjustment can only be made by the miller, because onlya practiced eye and touch can discover thevariation in the grinding and know when and how much adjustment is required to correct it.

The object of my invention is to prevent the variation in the grinding of meal and flour consequent upon the expansion and contraction of the spindle ot' the runner, caused by the heatingand cooling of the upper bearing of the same; and to this end my invention consists in having a number of longitudinal openings or apertures formed in the upper bearing of the spindle, in combination with a fan, which is secured to the spindle and revolves within a suitable casing below the bedstone, whereby a current of air is drawn into the casing and forced through the longitudinal apertures of the bearing of the spindle, and thereby both bearing and spindle prevented from heating, and consequently irom expansion, so that when the mill is once set to grind to a certain degree of fineness or coarseness it will so continue to grind with out any perceptible variation so long as the grinding-surfaces of the stones are in good working condition.

It also consists in a facile mode of setting the followers up to and around the spindle, all as will be hereinafter fully explained.

To enable others skilled in the art to which my invention appertains to fully understand the same, I will proceed to describe its construction and operation.

A represents a cast-iron or other suitable metal box, provided on two opposite sides with horizontally-projecting lugs a, and embedded in the face of the stationary or bed stone B. Depending from the under side of the box A, at points equidistant apart around the center, are four lugs, b, which extend entirely through the bed-stone and serve to steady the box. These lugs are cast hollow to receive keys 0, by means of which the boxes or followers are set up around the spindle as the latter becomes loose from any cause whatever. Through the center of the box A is an aperture of considerably larger diameter than the spindle through which it passes, and around this aperture, at points equidistant apart, are four radial mortises (shown by dotted lines in Fig. 2) adapted to receive the followers G, which at their inner ends conform to' the bearing-surface of the spindle I). These followers, at their rear ends, are inclined to correspond with the inclined face of the key 0. Each of the keys 0 terminates at bottom in a rounded shank, d, which is screw-threaded, and has a nut, g, fitted upon it. The upper beariug,f, of the spindle D is oflarger diameter than the spindle proper, and has a number of longitudinal openings or apertures, 0, made through it. Below the bearing f, and rigidly attached to the spindle, is a fan, E, which is adapted to revolve within a casing, F. This casing, at its upper end, is fitted over a flange projecting from the bottom of the boX A, and it is supported in position by a forked lever, (shown in Fig. 1,) whereby it may be raised or lowered to regulate the blast, or it may be supported in any other suitable manner. A hole of large diameter in the bottom of the casing, and surrounding the spindle, permits the air to be drawn into the casing by the action of the fan. The air thus drawn in by the fan is by the same means forced through the apertures 0 in the spindle, and thereby the latter prevented from heating or from changingits temperature, and thereby the variation in the grinding caused by the expansion and contraction of the spindle entirely overcome. The followers 0 are set up around the spindle-bearingf by means of the nuts h, which serve to draw the keys downward, and thus force the followers inward against the spindle.

Attached to the top of the box A, and surrounding the spindle D, is a circular disk, H, having a saucershaped cavity in its upper side to receive cotton saturated with oil or other suitable material to lubricate the upper bearing,f, of the spindle. A plate, I, fitting over the disk H, prevents dirt, dust, or any foreign substance from mixing with the lubrieating material.

The modification of the spindle represented by Fig. 3 of the drawings consists simply in having a sleeve fitted over a squared portion of. the upper spindle to form the upper hearing, instead of having that portion forming the bearing solid with the spindle.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The fan E, attached to the spindle D and revolving within the casin g F, in combination with the longitudinal apertures e in the upper bearing, f, of the spindle, when the former is used to force a current or currents of air through the apertures e of the bearing, in the manner and for the purpose substantially as described.

2. The keys 0, terminating at bottom in rounded screw-threaded shanks 0?, having nuts g fitted upon them, in combination with the lugs!) and followers 0, when arranged to operate in the manner specified.

The above specification of my improvements in the bush and spindle of grinding'mills signed this 16th day of July, 1863.

CORNELIUS BOLLINGER. Witnesses:

CHARLES SMITH, JAMES H. GRIDLEY. 

